Table 5 presents the summary of the tensile testing of the squeeze cast, LPPM, T-Mag, and ablation processes. The me- chanical properties listed are 0.2% offset yield strength, ulti- mate tensile strength, and total elongation at failure. Due to a limited supply of specimens, Table 5 lists actual test values and not averages since only one specimen from each location per process was tested. From the experimental results of the tensile tests, the ablation process exhibited the greatest average yield strength (96 MPa). For the ultimate tensile strength and elongation, the top two performing samples were those from the ablation and T-Mag processes. In particular, the ablation process exhibited much higher elongation (13.8% in average) than other processes, which is consistent with the investigation in the FPB tests, where no ablation samples could be broken. In all of the tested tensile specimens, the Mg alloy exhibited a large degree of work hardening, which was reasonably consis- tent across processes and locations. Due to the limited number of specimens tested, a correlation between location and me- chanical properties was not attempted. As seen from Table 5, the mechanical properties exhibited a large amount of scatter across all processes. The largest scatter was seen in the elonga-
Table 3. UBS for FPB Tests in Ascending Order for Each Casting Process (MPa)
tion-to-failure values. While the ablation process exhibited the best overall elongation, the process still exhibited a large degree of scatter between locations. The LPPM process exhibited the most scatter with regard to the elongation values.
(a)
(b)
Figure 11. SEM images of oxide films on the fracture surfaces of FPB test specimens taken from the control arms produced by LPPM process.
Figure 12. A two parameter Weibull plot for UBS data of FPB tests for the different casting processes.
44 International Journal of Metalcasting/Fall 2011
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